<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

</head>
<body>

<script>
    new Vue({
        data: {
            a: 1
        },
        created: function () {
            // `this` 指向 vm 实例
            console.log('a is: ' + this.a)
        }
    })
</script>
</body>
</html>